This is an excise tax upon the privilege of doing business as
     an artificial entity and of freedom from a general partnership
     liability enjoyed by those who own the stock.

Assuming, then, that this is the real nature of the tax, is it constitutional?

Unquestionably Congress may tax corporations organized under federal laws upon their franchises; any sovereignty may tax the creatures of its creation for the privilege of exercising their franchises; but how about corporations chartered by the states and doing purely an intrastate business?  A state confers on John Doe and his associates the privilege or franchise of doing business in a corporate capacity.  Can Congress impose a tax on the exercise of that privilege or franchise?  The power to tax involves the power to destroy.[1] If Congress can impose a tax of one per cent., it can impose a tax of ten per cent. or fifty per cent., and thus impair or destroy altogether the value of corporate charters for business purposes.  Does Congress possess such a power?  The Constitution puts no express limitation on the right of Congress to levy excises except that they shall be “uniform throughout the United States.”  But there are certain implied limitations inherent in our dual system of government.  The sovereignty and independence of the separate states within their spheres are as complete as are the sovereignty and independence of the General Government within its sphere.[2] Neither may interfere with or encroach upon the other.

[Footnote 1:  McCulloch vs.  Maryland, 4 Wheat., 316.]

[Footnote 2:  The Collector vs.  Day, 11 Wall., 113, 124.]

The right to grant corporate charters for ordinary business purposes is an attribute of sovereignty belonging to the states, not to the General Government.  The United States is a government of enumerated powers.  The Constitution nowhere expressly confers upon Congress the right to grant corporate charters, and it is well settled that this right exists only in the limited class of cases where the granting of charters becomes incidental to some power expressly conferred on Congress, e.g., the power to establish a uniform currency, or the power to regulate interstate commerce.  On the other hand, the right of the separate states to grant charters of incorporation is unquestionable.  By the Tenth Amendment of the Constitution it is expressly provided:  “The powers not delegated to the United States by the Constitution nor prohibited by it to the states are reserved to the states respectively or to the people.”  The Supreme Court long ago said:  “A state may grant acts of incorporation for the attainment of those objects which are essential to the interests of society. This power is incident to sovereignty."[1]

[Footnote 1:  Briscoe v.  Bank of Kentucky, 11 Peters, 257, 317.]

The power to grant the franchise of corporate capacity being therefore inherent in the sovereignty of the states, will not a tax imposed by Congress upon the exercise of the franchise constitute an interference with the power?  If so the tax is unconstitutional.